Reliabilist Epistemology

Reliabilism is an approach to epistemology that emphasizes the
truth-conduciveness of a belief-forming process, method, or other
epistemologically relevant factors. The reliability theme appears in
theories of knowledge, of justification, and of evidence.
“Reliabilism” is sometimes used broadly to refer to any
theory that emphasizes truth-getting or truth indicating
properties. More commonly it is used narrowly to refer to process
reliabilism about justification. This entry discusses reliabilism in
both broad and narrow senses, but concentrates on the theory of
justification.

It is generally agreed that a person S knows a
proposition P only if S believes P and P
is true. Since all theories accept this knowledge-truth connection,
reliabilism as a distinctive approach to knowledge is restricted to
theories that involve truth-promoting factors above and beyond the
truth of the target proposition. What this additional truth-link
consists in, however, varies widely.

Perhaps the first formulation of a reliability account of knowing
appeared in a brief discussion by F.P. Ramsey (1931), who said that a
belief is knowledge if it is true, certain and obtained by a reliable
process. This attracted no attention at the time and apparently did
not influence reliability theories of the 1960s, 70s, or 80s. Another
early reliability-type theory was Peter Unger’s (1968) proposal
that S knows that P just in case it is not at all
accidental that S is right about its being the case
that P. S’s being right about P amounts
to S’s believing truly that P. Its not
being accidental that S is right about P amounts to
there being something in S’s situation that makes it
highly probable that S would be right. David Armstrong (1973)
offered an analysis of non-inferential knowledge that explicitly used
the term “reliable”. He drew an analogy between a
thermometer that reliably indicates the temperature and a belief that
reliably indicates the truth. According to this account, a
non-inferential belief qualifies as knowledge if the belief has
properties that are nomically sufficient for its truth, i.e.,
guarantees its truth via laws of nature. This can be considered a
reliable-indicator theory of knowing. Alvin Goldman offered his first
formulation of a reliable process theory of knowing—as a
refinement of the causal theory of knowing—in a short paper on
innate knowledge (Goldman 1975).

In the 1970s and 1980s several subjunctive or counterfactual
theories of knowing were offered with reliabilist contours. The first
was Fred Dretske’s “Conclusive Reasons” (1971),
which proposed that S’s belief that P qualifies as
knowledge just in case S believes P because of reasons
he possesses that would not obtain unless P were true. In other
words, S’s reasons—the way an object appears
to S, for example—are a reliable indicator of the truth
of P. This idea was elaborated in
Dretske’s Knowledge and the Flow of Information (1981),
which linked knowing to getting information from a source through a
reliable channel. Meanwhile, Goldman also proposed a kind of
counterfactual reliability theory in “Discrimination and
Perceptual Knowledge” (1976). This theory developed the idea of
knowledge excluding “relevant alternatives”, an idea
already adumbrated in Dretske’s “Epistemic
Operators” (1970). In Goldman’s treatment, a person
perceptually knows that P just in case (roughly) she arrives at
a belief in P based on a perceptual experience that enables her
to discriminate the truth of P from all relevant
alternatives. On this approach, S’s knowing that P
is compatible with there being “radical” (hence
irrelevant) situations—for example, brain-in-a-vat
situations—in which P would be false although S
has the same experience and belief. Gail Stine (1976) explored this
approach with respect to knowledge, skepticism, and deductive closure
(i.e., the principle that one knows all that is implied—or all
that one knows to be implied—by what one knows).

Robert Nozick (1981) proposed a theory with similar contours, a
theory he called a “tracking” theory. In addition to truth
and belief, Nozick’s conditions for knowledge were: (1)
if P were not true then S would not believe
that P, and (2) if P were true, S would believe
that P. The first of the two tracking conditions was
subsequently called the “sensitivity” requirement. A
number of counterexamples have been produced to this condition (see
especially DeRose 1995). A similar tracking condition that has gained
attention recently is a “safety” condition. Safety can be
explained in slightly different formulations (see Ernest Sosa 1996,
2000; Timothy Williamson 2000; Duncan Pritchard 2005), including
“if S believes that P, then P would not
easily have been false”, or “in all of the nearest worlds
where S believes that P, P is
true”. Williamson classifies the safety approach as a species of
reliability theory (2000: 123–124).

Reliability theories are partly motivated by the threat of
skepticism. It is natural to think that if you know that P then
in some sense you “can’t be wrong”
about P. But what is the relevant sense of
“can’t”? Does it mean that your evidence
must logically preclude the possibility of error? If so, very
few propositions would be known. Reliability theories, in their
various ways, propose weaker but still substantial senses of
“can’t be wrong”. For example, the
relevant-alternatives theory allows that one can know that P
even if there are logically possible situations in which one’s
evidence is the same but P is false. But it insists that there
be no relevant possible situations in which one’s
evidence is the same but P is false. Such an account is not so
seriously threatened by skepticism.

Reliability theories of knowledge continue to appeal to
epistemologists, and permutations abound. The reliability theories
presented above focus on modal reliability, on getting truth
and avoiding error in possible worlds with specified relations to the
actual one. They also focus on local reliability, that is,
truth-acquisition in scenarios linked to the specific scenario in
question as opposed to truth-getting by a process or method over a
wide range of cases. Other reliabilisms focus on global
reliability: the reliability of the type of process or method used
across all or many of its applications.
Goldman’s Epistemology and Cognition (1986) combines
both local and global reliability in its account of
knowledge.

The first reliabilist approach to justification, and the
one most widely discussed, is process reliabilism. This was originally
formulated by Goldman in “What Is Justified Belief?”
(1979). Goldman begins by proposing some constraints or desiderata for
any account of justification. First, theories of justification should
specify conditions for justified belief that do not invoke the
justification concept itself, or any other epistemically normative
concepts such as reasonability or rationality. The aim—or hope,
at any rate—is to provide a “reductive” account of
justification that doesn’t rely, explicitly or implicitly, on
any notions that entail justification or other members of the same
family. This requirement has bite to it. For example, it might
p­reclude an analysis of justified belief in terms of
“evidence”, unless “evidence” can itself be
characterized in non-epistemic terms. What kinds of terms or
properties are appropriate, then, for constructing an account of
justification? Permissible concepts or properties would include
doxastic ones, such as belief, disbelief and suspension of judgment;
and any other purely psychological concepts, such as ones that refer
to perceptual experience or memory. Given the assumption that truth
and falsity are non-epistemic notions, they would also be perfectly
legitimate for use in analyzing justifiedness. Another admissible
element in an account of justifiedness, it was proposed, is the causal
relation.

Proceeding under these constraints, Goldman was led to the reliable
process theory as follows. (The main theory is addressed
to doxastic justifiedness—i.e., having of a justified
belief—rather than propositional
justifiedness—i.e., having justification for a proposition. It
will be the sole topic of our discussion.) First, examples were used
to show that whether or not a particular belief is justified depends
on how that belief is caused, or causally
sustained. Suppose that Sharon believes (justifiedly) a
conjunction of propositions, Q and R, from
which P logically follows. And suppose that, soon after forming
this conjunction of beliefs, Sharon also forms a belief
in P. Does it follow that Sharon’s belief in P is
justified? No. First, although Sharon believes Q and R,
those propositions may play no (causal) role in her coming to
believe P. She may form her belief purely by wishful
thinking. She hopes that P is going to be true, and
therefore (somehow) comes to believe it. Alternatively, suppose she
uses some kind of “reasoning” that begins with Q
and R. It is quite confused reasoning but serendipitously
leads to P. In neither case is her resulting belief in P
justified. This shows that a necessary condition on a belief to be
justified is that it be produced or generated in
a suitable way. What kinds of belief–forming processes
are suitable or proper, and what kinds are defective or
unsuitable?

One feature that wishful thinking and confused reasoning have in
common is unreliability. By contrast, which types of belief-forming
processes confer justification? They include standard perceptual
processes, remembering, good reasoning, and introspection. What do
these processes share? Reliability: most of the beliefs they produce
are true. (This formulation is slightly refined later.) Thus, the main
proposal of “What Is Justified Belief?” was that a
belief’s justifiedness is fixed by the reliability or
unreliability of the process or processes that cause it. Reliability
might be understood in a frequency sense (pertaining to what
occurs in the actual world) or a propensity sense (pertaining
both to actual-world and possible-world outcomes). Justification is
conferred on a belief by the truth-ratio (reliability) of the process
that generates it. Just how high a truth-ratio a process must have to
confer justification is left vague, just as the justification concept
itself is vague. The truth-ratio need not be 1.0, but the threshold
must surely be greater (presumably quite a bit greater) than .50.

A number of consequences were inferred from these main points, and
refinements were added. One consequence was that process reliabilism
is a “historical” theory. A reliable inferential process,
for example, confers justification on an output belief only if the
input beliefs (premises) are themselves justified. How could their
justifiedness have arisen? Presumably, by having been caused by
earlier applications of reliable processes. This chain must ultimately
terminate in reliable processes that themselves have no doxastic
inputs. Perceptual inputs are a good candidate for such
processes. Thus, on this approach, justifiedness is often a matter of
a history of personal cognitive processes. The historical feature of
process reliabilism contrasts sharply with traditional foundationalism
and coherentism, in which one’s concurrent mental states are the
only justification-determining factors.

These fundamental ideas were spelled out by Goldman in “What
Is Justified Belief?” (1979/2012) in a series of principles:
base-clause principles and recursive-clause principles. The initial
one was (1):

(1) If S’s
believing p at t results from a reliable cognitive
belief-forming process (or set of processes ), then S’s
belief in p at t is justified.

This principle may fit cases of perceptually caused beliefs and
other beliefs that make no use of prior doxastic states (as inputs),
but inferential beliefs seem to require a different principle. When a
belief results from inference, its justificational status depends not
only on the properties of the inferential process but also on whether
the premise beliefs of the inference are themselves justified. To
accommodate this, a slightly more complex principle was
introduced:

(2) If S’s
belief in p results from a belief-dependent process that is
conditionally reliable, and if the beliefs (if any) on which this
process operates in producing S’s belief in p
at t are themselves justified, then S’s belief
in p at t is justified.

By philosophical standards, these are not terribly complex
principles; and, perhaps they invoke only a smallish set of core
ideas. Thus, process reliabilism is a comparatively simple and
straightforward theory. Such simplicity has usually been viewed as a
virtue of the approach. (After all, theories in this territory are
trying to capture the intuitive conception of justification of
ordinary folk. How complex can their conception be? Ceteris
paribus, then, simple theories are preferable to more complex
ones.) Of course, matters are more complicated than the foregoing
principles convey. They ignore cases in which the agent has
“defeating” evidence for the proposition he or she comes
to believe. “What Is Justified Belief?” therefore proposed
a further principle to accommodate this additional detail. But we
shall not explore this further complication (to appreciate its
significance, however, see Beddor 2015).

The attractiveness of reliabilism can be illustrated by seeing how
it handles a challenging type of example. How might it handle directly
justified beliefs, for instance? Richard Feldman (2003) presents the
following case. Two bird-watchers, a novice and an expert, are
together in the woods when a pink-spotted flycatcher alights on a
branch. Both form a belief that it’s a pink-spotted
flycatcher. The expert is immediately justified in believing this but
the novice isn’t; the latter just jumps to this conclusion out
of excitement. Process reliabilism has adequate resources to handle
this case (Goldman 2008). The crucial difference between expert and
novice lies in the difference between their respective belief-forming
processes. The expert presumably connects selected features of his
current visual experience to things stored in memory about
pink-spotted flycatchers, securing an appropriate match between
features in the experience and features in the memory store. The
novice does no such thing; he just guesses. Thus, the expert’s
method of identification is reliable whereas the novice’s method
is unreliable.

Because of the influence—though hardly uncontested
influence—of this work on process reliabilism, as well as the
reliabilist work surveyed in section 1, many
commentators see epistemology as having undergone a major shift in
recent decades. Michael Williams writes:

Williams himself seeks to resist this revolution, but does not
dispute its occurrence. To pinpoint the core changes, it helps to
distinguish two types of approaches to justification:
“internalism” and “externalism”. Internalism
is usually identified as the dominant theme in epistemology’s
history since Descartes, continuing through most of the
20th century. Externalism is the new game in town, of which
reliabilism is a salient example. What are the main features of
internalism and externalism respectively?

There are two ways to fix what properties or states of affairs
qualify as justifiers, or J-factors, according to internalism. On one
option, a property or state of affairs F is a justifier for
agent S (at t) only if F is directly
accessible to S at t. On the second option, a
property or state of affairs F is a justifier for S
at t only if F is a mental state
of S at t. The first view is called
“accessibilism” and the second “mentalism”
(Feldman and Conee 2001). What is direct accessibility? Roughly, it
means knowability by some introspective or reflective
method. Externalism is, generally speaking, the denial of
internalism. For present purposes, it is a denial of both of the
indicated forms of internalism. Given these definitions, it is pretty
obvious that reliabilism must be a variety of externalism, because it
holds that being caused by a reliable process is a (prima
facie) justifier of a belief. But being reliably caused is
neither a (pure) mental state nor something directly accessible in the
intended sense. Being reliably caused is a matter of
truth-conduciveness, and truth conduciveness is not introspectively or
reflectively accessible. Similarly, reliabilism holds that processes
used in the past may be justificationally relevant to a currently held
belief (because of the historicity of justifiedness). But processes
used in the past are not mental states concurrent with the target
belief, and are not, in general (if at all), directly accessible to an
agent now. Thus, since reliabilism doesn’t require
these properties to hold of J-factors, it is a form of externalism. Of
course, reliabilists don’t shy away from this consequence; they
are generally happy with these features of their package. First,
reliability theories avoid the stringent conditions of some
internalist theories, conditions that are arguably too demanding to
account for the extent of justified belief. Second, examination of
cases strongly supports process reliability as central to
justification. Thus, although tweaking may be needed, reliabilists see
externalism as a good path for epistemology to follow.

Although the details of the internalism/externalism debate are
complex—and won’t be pursued further here [see SEP entry
on internalist vs. externalist conceptions of epistemic justification]—it
should be clear that there is
a major dispute here, so that a departure from the internalist
perspective, as process reliabilism advocates, is indeed a substantial
matter for epistemologists. Hence Williams’s talk of a
“revolution”.[1]

A number of problems for process reliabilism were identified in its
own initial formulation or shortly thereafter. One type of problem is
that its conditions seem too weak for justifiedness. Does it suffice
for a belief’s justifiedness that it be caused by a reliable
process? Mustn’t it also meet a meta-justification condition,
for example, a “\(J \rightarrow JJ\)” condition, according
to which if one’s belief in p is justified, then one also
justifiedly believes that one justifiedly believes p? Explicit
use in a theory of the JJ principle itself, of course, would violate
the constraints for a reductive account of justification. An account
of justification (or at least a “base-clause” component of
such an account) should not feature the very notion of justification
itself. All right, but maybe one could add a requirement that the
agent have a reliably-caused higher-order belief that his/her
first-order belief is reliably caused. This proposal, unfortunately,
is both too strong and too weak. It is too strong because agents do
not constantly monitor their first-order beliefs for reliability and
form higher-order beliefs about them. To require such continual
monitoring as a condition of first-order justifiedness would be
excessive. Too few beliefs would qualify as justified. Second, if one
feels the need for higher-level requirements, why should they stop at
the second level? Why not require a third-order reliably formed
belief, and a fourth-order one, etc.? Here looms the threat of an
infinite regress. Third, why should a critic who regards simple
reliable causation as insufficient for justification be satisfied with
any higher-order requirements? If simple reliable causation at the
first level is insufficient, why should justification be guaranteed by
reliability at any higher level? Some reliabilists will be inclined to
strengthen the requirement for justification by adding
a negative requirement, namely, that the agent not
believe that her first-order belief is unreliably caused
(or—what is arguably more in keeping with the spirit of
reliabilism—that the agent not reliably believe that
her first-order belief is so-caused).

A second problem for process reliabilism is the “new
evil-demon problem” (Cohen 1984; Pollock 1984; Feldman 1985;
Foley 1985). Imagine a world where an evil demon creates non-veridical
perceptions of physical objects in everybody’s minds. All of
these perceptions are qualitatively identical to ours, but are false
in the world in question. Hence, their perceptual belief-forming
processes (as judged by the facts in that world) are unreliable; and
their beliefs so caused are unjustified. But since their perceptual
experiences—hence evidence—are qualitatively identical to
ours, shouldn’t those beliefs in the demon world be justified?
Evidently, then, reliabilism must deliver the wrong verdict in this
case.

One line of response to this problem is to argue that it
doesn’t follow from the low truth-ratio of processes in the
demon world that the beliefs must be categorized as unjustified
according to reliabilism, because reliabilism need not use the
processes’ truth-ratios in the world of the example as
the standard of evaluation. That this is the standard was assumed in
posing the objection; but it wasn’t clearly so stated in the
formulation of reliabilism. It is open to reliabilists to chart a
different course, to choose a different standard of process
reliability. Perhaps the appropriate domain or standard is the
truth-ratio of the processes in the actual world. However,
the plausibility or rationale for such an alternative standard is not
obvious. We return to this issue in section 4
and again in sub-section 5.2.

A third objection to reliabilism, which also surfaced early on,
argues that reliability isn’t sufficient for justification. The
principle example here is due to Laurence BonJour (1980). His
strongest example describes a subject, Norman, who has a perfectly
reliable clairvoyance faculty, but no evidence or reasons for or
against the general possibility of a clairvoyant power or for or
against his possessing one. One day Norman’s
clairvoyance faculty produces in him a belief that the President is in
New York City, but with no accompanying perception-like experience, just the belief. Intuitively, says BonJour, he isn’t justified
in holding this belief; but reliabilism implies that he is. Similar
examples were offered by Keith Lehrer (1990) and Alvin Plantinga
(1993). We will re-visit these cases in
section 4.

A fourth problem for reliabilism—perhaps the most discussed
problem—is the generality problem. Originally formulated by
Goldman in “What Is Justified Belief?”, it has been
pressed more systematically by Feldman (1985) and Conee and Feldman
(1998). Any particular belief is the product of a token causal process
in the subject’s mind/brain, which occurs at a particular time
and place. Such a process token can be “typed”, however,
in many broader or narrower ways. Each type will have its own
associated level of reliability, commonly distinct from the levels of
reliability of other types it instantiates. Which repeatable type
should be selected for purposes of assigning a reliability number to
the process token? If no (unique) type can be selected, what
establishes the justificational status of the resulting belief? Conee
and Feldman (1998) lay down three requirements for a solution to the
generality problem. First, the solution must be
“principled” rather than ad hoc. Second, the type
selected should have a reliability plausibly correlated with the
justificational status of the ensuing belief. Third, the solution
must remain true to the spirit of reliabilism. They argue, however,
that prospects for finding such a solution are bleak.

A fifth problem, the problem of bootstrapping (or “easy
knowledge”), is due to Jonathan Vogel (2000) and Stewart Cohen
(2002). Roxanne is a driver who believes whatever her gas gauge
“says” about the state of her fuel tank, although she has
no antecedent reasons to believe it is reliable. Roxanne often looks
at the gauge and arrives at beliefs like the following: “On this
occasion the gauge reads ‘F’ and F”, where
the second conjunct implies that the tank is full. Since the
perceptual process by which she arrives at the belief that the gauge
reads ‘F’ is reliable, and so is the process by which she
arrives at the belief that the tank is full (given that the gauge
functions completely properly). According to reliabilism, therefore,
her belief in the indicated conjunction should be justified. Now
Roxanne deduces the proposition, “On this occasion, the gauge is
reading accurately.” And from (multiple examples of) this she induces
“The gauge is reliable (in general)”. Finally, with a
little more deduction she concludes she is justified in
believing that her gas tank is full. Since deduction and
induction are reliable processes, Roxanne must also be justified in
believing that her gas gauge is full. Suppose Roxanne does this
repeatedly, without ever getting independent information about the
gauge’s reliability. Is she really justified in this? Definitely
not, say Vogel and Cohen, because such bootstrapping amounts to
epistemic circularity; it sanctions its own legitimacy (no matter
what). So reliabilism gets this wrong.

A final problem (for present purposes) is the so-called
“value problem”. Plato claimed that knowledge is more
valuable than true belief, and many authors concur with his
suggestion. This raises the puzzle of why this should be so. What
extra value does knowledge have as compared with true belief? Focusing
on process reliabilism, the question is whether reliabilism can
explain this value difference. (Although our present topic is
justification, not knowledge, this organizational matter will be
ignored.) Reliabilism’s answer, it would seem, is that causation
by a reliable process confers extra value on a belief so as to make it
justified and/or knowledge. This suggestion is criticized by several
philosophers: Jones (1997), Swinburne (1999), Zagzebski (1996, 2003),
Riggs (2002), and Kvanvig (2003). Zagzebski’s example brings
the point home. Consider a cup of espresso, she says, that is produced
by a reliable espresso machine.

[T]he reliability of the source [the expresso
machine] does not … give the product an additional boost of
value. If the espresso tastes good, it makes no difference if it comes
from an unreliable machine. (2003: 13)

Similarly, the epistemic value of a belief cannot be raised by the
reliability of the source.

Reliabilists have offered a number of responses to these various
problems and objections. Having already considered a response to the
first problem (in section 3), we turn next
to the second and third: the new evil-demon problem and the
clairvoyance problem.

One response to the clairvoyance problem is to
distinguish prima facie from ultima facie
justification. Process reliabilism is typically couched as a theory
of prima facie justification: if S’s belief
that p is the result of a reliable process, but it is
maintained in the face of (sufficiently strong) countervailing
considerations, S’s belief will not count as ultima
facie justified (that is, it will not be justified full
stop). Thus one possibility is that Norman’s belief that
the president is in New York is not ultima facie justified
because it is defeated. A response along these lines was briefly
suggested by Goldman (1986: 112).

Of course, a response along these lines needs to be supplemented
with a theory of defeat. Goldman’s original 1979 article
proposed that S’s belief is defeated as long as there are
reliable (or conditionally reliable) belief-forming processes
available to S such that, if S had used those processes
in addition to the process actually used, S wouldn’t have
held the belief in question. However, it is not entirely clear how
this “Alternative Reliable Process” account would help in
the case of Norman; what’s more, some have deemed this theory of
defeat problematic on other grounds (see Beddor 2015 for
objections). But even if the Alternative Reliable Process account is
deemed wanting, presumably some superior account of defeat is
possible. (Indeed, it seems that any adequate account of
justification—not just those of a reliabilist bent—owes us
some story about defeat.) And it may be that the right account of
defeat—whatever it is—will help process reliabilism
capture the intuition that Norman’s belief is unjustified.

A different response to the clairvoyance objection is to concede
that being the result of a reliable process isn’t sufficient for
even prima facie justification; some further condition must
be met. Jack Lyons (2009, 2011) develops a novel reliabilist response
to the clairvoyance challenge along precisely these lines. According
to Lyons, in order for a non-inferential belief to be justified, it
must be the result of a “primal system”.

Drawing on research in cognitive science, Lyons
proposes that a primal system is any cognitive system that meets two
conditions: (i) it is “inferentially opaque”—that
is, its outputs are not the result of an introspectively accessible
train of reasoning, (ii) it develops as a result of a combination of
learning and innate constraints (2009: 144). For Lyons, our perceptual
systems are paradigmatic examples of such primal systems.

How does this help with the clairvoyance objection? According to
Lyons, Bonjour’s presentation of the Norman example invites the
assumption that Norman’s clairvoyance was the result of some
recent development—e.g., “a recent encounter with
radioactive waste” or a “neurosurgical
prank”—not the result of some combination of learning and
innate constraints (2009: 118–119). Given this assumption,
Norman’s clairvoyance-based belief is not the result of a primal
system, hence it is not prima facie justified. Lyons goes on
to argue that if we consider variants of the Norman case where the
agent’s belief is the result of a primal system, our intuitions
shift. Lyons asks us to consider the case of Nyrmoon, a member of an
alien species, for whom clairvoyance is a normal cognitive capacity.
(To make this more plausible, Lyons asks us to imagine that
Nyrmoon—and his conspecifics—can detect “highly
attenuated energy signals from distal events”.) However, Nyrmoon
is so unreflective that he has no beliefs about the reliability of his
clairvoyance. Lyons contends that, in contrast with Norman,
Nyrmoon’s clairvoyance-based beliefs are justified. He takes
this to support the claim that being the result of a primal system
that is also reliable is sufficient for the justifiedness of
noninferential beliefs.

Thus far we have looked at responses that focus on the clairvoyance
objection. Another strategy is to try to solve both the new evil demon
problem and the clairvoyance problem at one fell swoop by opting for a
variant of process reliabilism. This variant, originally called
“two-stage reliabilism” (Goldman 1992), has been endorsed
more recently under a more appealing label: “approved-list
reliabilism” (Fricker forthcoming). The approach is inspired by
the following conjecture about how attributors make justification
attributions. In a preliminary stage, opinions are formed about the
reliability of assorted belief-forming processes, using observation
and/or inference to draw conclusions about the track-records of these
processes in the actual world. They thereby construct mental lists of
reliable and unreliable processes: lists of approved and disapproved
processes (respectively). In the second stage of the operation, they
deploy these lists to make judgments about particular beliefs (actual
or hypothetical). If somebody’s belief was caused by a process
that is on their approved list—or resembles one on their
approved list—they consider it justified. If it is caused by a
process on their disapproved list, it is classed as unjustified.

How would approved-list reliabilism explain intuitive judgments in
the clairvoyance case? Presumably, an ordinary attributor would not
have a clairvoyance process on either of her lists. But she might well
have processes like extra-sensory-perception or telekinesis on her
list, especially her disapproved list. The process or faculty Norman
uses to arrive at his belief about the President sounds very similar
to one of those obscure and suspect powers. Hence, Norman’s
belief is intuitively classified as unjustified. This is despite the
fact that—as potential attributors are told—Norman’s
clairvoyance process is thoroughly reliable. This is how approved-list
reliabilism explains our judgments in the clairvoyance case. What
about the new evil-demon case? Again, it is assumed as background that
a potential attributor constructs lists of belief-forming processes,
one for approved process types and one for disapproved
types. Perceptual processes (of various sorts) would be on the
approved list. Since the people in the evil-demon case use perceptual
processes that would be on the approved list, an attributor would
consider their resulting beliefs justified—even though s/he is
told that the perceptual processes in the evil-demon world are
unreliable. The whole idea of approved-list reliabilism is that the
two stages—list construction and list application—are
quite distinct. This enables the theory to predict responses to
justification questions that comport with our actual inclinations or
intuitions.

Approved list reliabilism is a theory of the factors that influence
our attributions of epistemic justification. It is thus
naturally construed as an attributor theory—a theory of
the conditions under which a justification attribution (that is, a
sentence of the form, “S is justified in
believing p”) is judged to be true or false. In this
regard, it parallels attributor theories of knowledge (e.g., DeRose
1992, 2009). There are different ways of developing an approved-list
attributor theory more precisely. For instance, a contextualist
implementation might hold that a justification attribution is true if
and only if the subject’s belief-forming process belongs to the
speaker’s approved list. Alternatively, one could adopt an
assessor-relativist implementation, according to which the
truth-conditions of justification attributions are relativized to
contexts of assessment (cf. MacFarlane 2005). An assessor-relativist
version of the approved list might hold that a justification
attribution is true at a context of assessment if and only if the
subject’s belief-forming process belongs to the assessor’s
approved list.

A similar strategy for solving the New Evil Demon problem is to
distinguish two different ways a process can be reliable. Suppose we
inhabit the actual world (@), and we’re evaluating a
subject S who inhabits some other world ws. Then there
are two different things we could mean when we say
that S’s belief-forming process is reliable: we could
mean that it’s reliable relative to @, or we could mean that
it’s reliable relative to ws (Sosa 1993,
2001). Comesaña (2002) uses this distinction to provide
a solution to the new evil demon problem cast in the framework of
two-dimensional semantics (Stalnaker 1999). On Comesaña’s
proposal, the sentence, “S is justified in
believing p” has two readings: (i) that S’s
belief-forming process is reliable relative to @, (ii)
that S’s belief-forming process is reliable relative to
ws. If ws is a demon world, then reading (i) will be true,
but reading (ii) is false. While Comesaña’s use of
two-dimensional semantics has drawn recent criticism (Ball and
Blome-Tillman 2013), the
basic strategy of solving the New Evil Demon problem by appealing to
two types of reliability remains popular. (A different promising
approach to the New Evil Demon Problem, the “normality
approach” is presented in section 5.2
below.)

The fourth problem posed in section 3
is the generality problem. Epistemologists who worry about process
reliabilism because of the generality problem usually assume that a
“solution” to this problem will consist in a formula for
identifying a unique process type given any specified case (assuming
the case is specified in reasonable detail). That is, pretty clearly,
what Conee and Feldman mean to require. Some epistemologists have
tried to provide such a formula, and some of them sound on the right
track (e.g., Alston 1995; Beebe 2004). James Beebe, for example, says
that a pertinent type will, first of all, be an information-processing
procedure or algorithm. Of course, there will often be indefinitely
many types of this kind, of varying reliability. To pick out the
appropriate type, Beebe offers the following
instructions. Let A be the broadest such type. Choose a
partition that is the broadest objectively homogeneous subclass
of A within which the token process falls, where a class is
objectively homogeneous if no statistically relevant partition
of S can be effected. This is an interesting idea, but there
remains the lingering worry that there may always be a set of
different conditions that meet Beebe’s standards, not a unique
one.

A different kind of approach is less optimistic about finding a
formula to pinpoint a unique type for each process token. This
approach is less sanguine about what the philosopher can do here.
However, this need not put any special pressure on process
reliabilism. It may be a problem that faces any theory of doxastic
justifiedness, at least any theory that highlights the causal
provenance of a target belief. (And this is probably all viable
theories.) This is the tack taken by Comesaña (2006). He argues
that the generality problem is not a special problem for
reliabilism, but one shared by all epistemologies of justification,
including Feldman and Conee’s own evidentialist theory. As
Comesaña notes, every adequate epistemology needs an account of
the basing relation, and any attempt to explain the basing relation
ultimately runs into the generality problem, or something very similar
to it. Michael Bishop (2010) argues for the same conclusion on
different grounds. According to Bishop, the generality problem will
arise for any theory that allows for the possibility of reflective
justification—that is, having a belief B that is
justified on the basis of one’s knowledge that one
formed B via a reliable form of reasoning.

But if no formula is proposed for selecting the uniquely correct
process type, isn’t it a mystery how attributors converge on the
same classifications (justified vs. unjustified) a large percentage of
the time? Yet there does seem to be such convergence. (Think about
all of the easy cases, not the hard ones.) Can this be explained? If
so, will the explanation sit comfortably with process reliabilism?
Erik Olsson (forthcoming) calls our attention to a well-supported
psychological theory about conceptualization
called basic-level theory. It is mainly due to the work of
Eleanor Rosch in the 1970s (Rosch et
al. 1976). Rosch and her
collaborators studied the deployment of taxonomically related concepts
like “animal”, “dog”, and
“Labrador”. In such a taxonomy, one term is a
superordinate concept (“animal”), another is an
intermediate-level concept (“dog”), and a third is a
subordinate concept (“Labrador”). It turns out that
intermediate-level concepts have a privileged status, and are
therefore called “basic-level” concepts. Basic-level
concepts are overwhelmingly preferred in free naming, are the first
concepts acquired by children, and occur more frequently in text. It
was also demonstrated that people tend to converge on reports in using
basic-level concepts. In one study psychologists found that, out of
540 responses, 530 to 533 converged on the same word for naming a
physical object (Rosch et al. 1976). Olsson suggests that basic-level theory calls into
question Feldman and Conee’s contention that in the absence of contextual cues,
there is no single intuitive process-type to which a given process
token corresponds. In a related vein, Jönsson (2013) showed
subjects clips in which characters arrived at various conclusions, and
then asked the subjects to specify how the characters arrived at
their beliefs. Subjects converged on the choice of verbs describing
the belief-formation processes, even without linguistic cues to guide
the process-typing task. A follow-up experiment (Jönsson 2013)
found a correlation between subjects’ estimates of the
reliability of the characters’ belief-forming processes and
subjects’ judgments about whether the characters were justified
in holding the beliefs in question. Thus there is some evidence that
folk psychological propensities lead to us to converge on
belief-typing tasks, and that our reliability assessments track our
justification judgments.

Consider now the fifth and sixth problems
of section 3: the bootstrapping and
extra-value problems. Brief responses will be given to each. As Cohen (2002)
points out, reliabilism is not unique in facing the bootstrapping
problem. Indeed, it is faced by all theories that exhibit what he
calls “basic knowledge” structure. Moreover, as van Cleve
(2003) effectively demonstrates, theories that do not allow for basic
knowledge lead to (wide-ranging) skepticism.

If we wish to allow for basic knowledge, can we still give a
principled explanation of why some forms of bootstrapping seem
illegitimate (for example, the case of Roxanne)? This is an area of
active research. One suggestion is that illegitimate forms of
bootstrapping involve No Lose Investigations. Roughly, a No
Lose Investigation into a hypothesis h is an investigation that
could never, in principle, count against h. (For suggestions
along these lines, see Kornblith 2009; Titelbaum 2010; Douven and Kelp
2013.) Another suggestion is that illegitimate forms of bootstrapping
all involve epistemic feedback (Weisberg 2010). Suppose an
agent believes premises \(p_1\ldots p_n\), from which she infers
lemmas \(l_1\ldots l_n\), from which she in turn infers a
conclusion c. Epistemic feedback is present when the
probability of c conditional on \(l_1\ldots l_n\) is greater
than the probability of c conditional on \(p_1\ldots p_n\).
Roxanne’s case can be understood in these terms. She first
believes various premises about the gas gauge readings (e.g., The
gas gauge read full at time \(t_1\); the gauge reads half-empty at
\(t_2\)). She then infers various lemmas about the state of the
gas tank (e.g., The tank was full at \(t_1\); the tank was
half-empty at \(t_2\)). Finally, by conjoining these premises
with these lemmas, she comes to believe the conclusion: The gas
tank is reliable. The probability of this conclusion conditional
on just the lemmas (that is, the beliefs about the state of the gas
tank) is higher than the probability of the conclusion conditional on
the premises (that is, the gas gauge readings). Perhaps by imposing a
ban on either No Lose Investigations or epistemic feedback (or both),
we can account for the intuition about Roxanne, while still allowing
for basic knowledge. (For an overview of various responses to the
bootstrapping problem, see Weisberg 2012.)

The value problem is also one that may be questioned from the
start. Was Plato right to claim that knowledge has more value than
true belief? This is debatable. However, let us presume this value
claim to be correct. A sophisticated account of value should be able
to account for one true belief having more value than another true
belief in virtue of its external relations to other events,
specifically, the kind of process that generated it. A strong case is
made for this—together with compelling examples—by Wlodek
Rabinowicz and Toni Roennow-Rasmussen (1999; also see Rabinowicz and
Roennow-Rasmussen 2003). What is of final value may nonetheless have
this value for its own sake in part because of its relational
properties (Kagan 1992).

One class of such things, discussed by Rabinowicz and
Roennow-Rasmussen, involve cases in which a thing is valued for its
own sake in virtue of its special relationship to another object,
event, or person.

An original, say, an original work of art, may be
valued for its own sake precisely because it has the relational
property of being an original rather than a copy. Its final value
supervenes, in part, on its special causal relation to the
artist. Princess Diana’s dress may be another case in point. The
dress is valuable just because it has belonged to Diana. This is what
we value it for…. [T]here are innumerable examples of a similar
kind: Napoleon’s hat, a gun that was used at Verdun, etc. In all
these cases, a thing acquires a non-instrumental value in virtue of
its causal relation to some person, object or event that stands out in
some way (Rabinowicz and Roennow-Rasmussen 1999:
41).

Similarly, states of true belief that are instances of knowledge
might have higher final value because they have the relational
property of being caused by a reliable belief-forming process.

As we have already seen, a crucial question that faces reliability
theories concerns the domain in which a process is assessed for
reliability. Several of the most-discussed problem cases for
reliabilism placed this question at center stage. In the new
evil-demon case, for example, is it the world of the demon at which
the reliability of perception is to be assessed, or is it the actual
world (or the world of the assessor)? Recently a new type of answer
has been floated by at least two writers. The new answer introduces
the notion of normal conditions for the use of a given
process or method, and suggests that reliability should be measured,
or assessed, only in terms of how well it works in normal conditions
(for the selected process or method).

For example, Jarrett Leplin (2007, 2009) rejects the common view of
reliable processes/methods as those that produce a high ratio of
truths to falsehoods. In its place, Leplin advances a conception of
reliability according to which a process/method is reliable if it
would never produce or sustain false beliefs under normal
conditions. As Leplin notes, this is a “subjunctive version of
reliabilism”, akin to Nozick’s treatment of knowledge
(Leplin 2007: 33; 2009: 34–35).

How should we understand “normal conditions”? Leplin
suggests:

[C]onditions normal for a method are conditions
typical or characteristic of occasions and environments in which the
method is usable or applicable, whether or not it is in fact then or
there used or applied. My thermometer is not (for the most part)
usable under extreme conditions. (Ordinary) perception fails in the
dark. It might happen that on all actual occasions… of a
method’s use, the conditions are atypical of occasions
on which it is usable. Then, despite the method’s reliability,
the preponderance of the beliefs it yields could be false. (2009:
37–38)

According to this account, perceptual beliefs of people in the
demon world, for example, can now be judged to be justified because
perceptual belief formation is a reliable process. It doesn’t
matter that perception isn’t reliable in their
environment; it suffices for the process to confer justification that
it be reliable in normal worlds.

Christensen (2007) raises the question of whether Leplin’s
conception of reliability is too strong. He suggests that there are
reliable processes (consulting the Encyclopedia, facial
recognition) that sometimes yield false beliefs even when operating
under normal conditions. One reason that it’s difficult to
judge the force of this objection is that the notion of “normal
conditions”, even given Leplin’s clarifications, remains
vague (which is not obviously a problem with the analysis; cf. Leplin
2009). At the very least, Leplin’s “normality”
approach offers a promising variant of traditional reliabilism, though
Leplin’s full story (not recounted here) is quite complicated
and not easily assessed.

An even more complex normality approach is presented by Peter
Graham (2012). Graham draws on an etiological account of
function due to Larry Wright (1973) and Ruth Millikan (1984), among others, to advance a
theory of epistemic entitlement (= justification) in terms of proper
functioning. A compact statement of his theory is this:

[A] belief enjoys a kind or source of prima
facie entitlement if and only if it is based on a normally
functioning process that has reliably forming true beliefs as an
etiological function. (2012: 472)

Given this basic theoretical framework, Graham draws a very similar
conclusion for the brain-in-the-vat case as that drawn by Leplin for
the demon-world case:

What the brain-in-a-vat case suggests is that
entitlement persists even when not in normal conditions, as long as
the process is functioning normally. (2012: 471)

Like Leplin, then, Graham uses a normality approach to address some
familiar counterexamples to process reliabilism. Whether one or more
of these normality approaches fully achieves the end at which it aims,
which remains to be seen, they certainly introduce a fresh and
well-motivated angle that holds promise for dealing effectively with
familiar counterexamples.

Most versions of reliabilism are “individualistic” in
at least two senses. First, they focus on the justificatory status of
a belief of an individual agent. Second, they make the justificatory
status of such a belief depend entirely on the reliability of
processes that take place within her or his head. Recently, a number
of authors have explored versions of reliabilism that revise or
abandon these individualistic assumptions.

Sanford Goldberg (2010) advances a distinctive view of testimonial
belief that abandons the second individualistic assumption, which he
calls, “Process Individualism”. On Goldberg’s view,
a proper assessment of the justificatory status (hereafter, J-status)
of a testimonial belief requires

an assessment of the reliability of cognitive
processes that take place in the mind/brain(s) of the
subject’s informant(s). (Goldberg 2010: 2, emphasis
original)

One of the ways that Goldberg motivates this “extendedness
thesis” is via the following sort of case (chap. 4). An
informant (A) forms a perceptual belief that p, which
she conveys via testimony to an audience (B), who then comes to
believe p. However, A’s perceptual belief
that p was formed in a way that falls just shy of the threshold
for justification, perhaps because it is based on a momentary glance,
or formed in poor lighting conditions. Goldberg contends
that B’s testimony-based belief that p does not
amount to knowledge. What’s more, the reason why it does not
amount to knowledge is that it is not justified. After all, the belief
could well be true, and free from Gettierization. (For an overview of
the Gettier Problem, see the entry on the Analysis of Knowledge.) But
if B’s belief that p is not justified, this
justificatory failing is not due to any unreliability
in B’s mental processing of A’s testimony;
it’s rather due to the fact that A’s original
belief that p was insufficiently justified. Goldberg thus
concludes that the J-status of testimonial beliefs are importantly
affected by the reliability of the testifier’s cognitive
processes.

A different new wrinkle in reliabilist epistemology has recently
emerged in social epistemology. It considers a non-traditional kind of
agent and asks what it takes for such an agent to have justified
beliefs. Could process reliabilism be applicable here too? The kind of
agent in question is a collective agent. Collective, or group, agents
are “plural subjects”. They are entities treated as
subjects in the sense that they are assumed to have propositional
attitudes like desires, intentions, goals, beliefs, judgments, etc. We
routinely speak this way in everyday discourse, and even in formal or
legal contexts, in which corporate bodies are assumed to have the same
kinds of attitudes that individuals have. We ask whether the CIA or
the FBI “knew” that certain Al Qaeda perpetrators of the
9/11 attacks had been taking flight lessons in the United States. In
asking this question, one assumes that the CIA and the FBI are the
bearers of beliefs or information; in other words, they have a
“psychology” of some sort (not to say conscious
psychological states). Working in this framework, a number of
philosophers pose the following question: under what circumstances
does a group have a certain belief? It is widely assumed that the
various belief-states of the group’s members are
important determiners of whether the group as a whole has a belief
with the same content. For example, Margaret Gilbert (1989) offers
what she calls the “joint acceptance account” of group
belief:

A group Gbelieves that p if
and only if the members of G jointly accept that p. The
members of Gjointly accept that p if and only
if it is common knowledge in G that the members of G
individually have intentionally and openly … expressed their
willingness jointly to accept that p with the other members
of G. (1989: 306–307)

This account of group belief is not widely accepted, but this is
incidental for present purposes. It is an early proposal for
formulating conditions of group belief. The main issue discussed here,
however, is not conditions for group belief, but conditions
for the justificational status of group beliefs. This kind of
question has been little discussed within epistemology. Only with the
emergence of social epistemology—and, more specifically, with a
recognition of the collective branch of social
epistemology—has it come clearly into focus.

The idea that process reliabilism might be a viable approach to
collective justifiedness was first broached by Frederick Schmitt
(1994), but with considerable tentativeness. A more developed
reliabilist approach is presented in Goldman 2014.

Goldman’s (2014) proposal makes use of List and Pettit’s
2011 framework for describing group beliefs, which we will briefly
review. It is widely thought that a group’s beliefs are
determined—in some way—by the individual beliefs of the
group members (List and Pettit 2011: 64). How exactly does this
determination work? Different candidate answers to this question can
be represented by different belief (or judgment) aggregation functions
(BAFs), which take as inputs beliefs of individual agents, and produce
as outputs group beliefs. A burgeoning literature is devoted to
discussing plausible requirements on BAFs. For instance, one might
require: (1) A BAF admits as input any possible profile of individual
beliefs (doxastic attitudes) toward the propositions on an agenda, and
the individual attitudes are consistent and complete (“universal
domain”). (2) The BAF produces as output consistent and complete
group attitudes towards the propositions on the agenda
(“collective rationality”). (3) All individuals’
attitudes are given equal weight in determining the group attitudes
(“anonymity”). And so on. Although each of these (plus
additional) conditions seem initially plausible, a number of
impossibility theorems have been proved that various combinations of
such desiderata cannot be jointly satisfied. This raises many
intriguing problems, which are not explored here.

Nothing has been said thus far about justification. What we might
seek is something analogous to a BAF, namely, a justification
aggregation function (JAF). Assuming that group G forms a
belief in p in conformity with some BAF and its members’
beliefs vis-à-visp, what must be true of the
J-statuses of those members’ beliefs (and other attitudes) with
respect to p for it to be true that G’s belief is
justified? If none of its members’ beliefs are
justified, then presumably G’s belief won’t be
justified either. A larger question is how—or whether—the
justifiedness of members’ beliefs is automatically transmitted
toward the group’s justifiedness.

Goldman argues for treating this transmission on the model of
inference within an individual agent. In the individual case,
premise beliefs generate beliefs in a conclusion, and the J-status of
the conclusion belief depends on the J-statuses of the premise
beliefs. Special epistemic relations hold between states and epistemic
statuses within a single individual. The fact that another
person is justified in believing a proposition Q doesn’t
give me justification for believing something implied
by Q. What about relations between a group and its members? The
suggestion is made that this is (or can be) an intimate relation. Just
as justifiedness can be transmitted intra-individually, it can be
transmitted within a group and its membership. Process reliabilism can
then be brought in to capitalize on this parallel. According to
process reliabilism for individuals, inferential justification depends
on two factors: (a) the justifiedness of the premise beliefs and (b)
the conditional reliability of the inferential process
used. In the collective belief case group justification depends on two
analogous factors: (a) the justifiedness of the members’
beliefs, and (b) the conditional reliability of the JAF: the function
that maps member justifiedness into group justifiedness.

The analogy between the individual and the aggregative cases is not
perfect, however. In cases of an individual’s inference, it is
plausible to require all premise beliefs to be justified in
order for the conclusion to be justified. This is too strong a
requirement for the collective case, however. Surely a group can
attain justified belief even if, say, only 95% of the members believe
it justifiedly. Goldman handles group justifiedness, in the end, by
talking about degrees of justifiedness for a group, arising
from assorted distributions of member justifiedness. In particular,
the following principle is proposed:

(GJ) If a group belief
in P is aggregated based on a profile of member attitudes
toward P, then ceteris paribus the greater the
proportion of members who justifiedly believeP and
the smaller the proportion of members who justifiedly
rejectP, the greater the group’s grade of
justifiedness in believing P (Goldman 2014:
28).

With this as background, the idea is introduced that group
justifiedness can arise through a diachronic process, in which
members’ severally acquire justified or unjustified beliefs in
the target proposition in accord with process reliabilist principles
for individuals. The J-statuses of these individual beliefs then
determine—via process reliabilist principles—the
J-statuses of the group beliefs.

Historically, reliabilism has been offered as an account of the
justificatory status of full or outright belief. However, it’s
widely thought that beliefs come in degrees: a person might believe
that it’s sunny and also believe that it’s Monday, but
have a higher degree of belief in the former than the latter. This
raises the question: can reliabilism be extended to provide an account
of the justificatory status of degrees of belief?

Formal epistemologists and decision theorists have long been
interested in different “scoring rules”—functions
that measure the accuracy or inaccuracy of degrees of belief
(hereafter, credences). For example, one widely discussed scoring rule
is the Brier score (Brier 1950). Let \(C(p)\) be an
agent’s credence in p; let \(T(p)\) be p’s
indicator function, which equals 1 if p is true, and 0
if p is false. \(C(p)\)’s Brier score is calculated by
the formula:

\[
(C(p)-T(p))^2
\]

Thus a credence of 1 in a true proposition will get a Brier score
of 0—the best score possible. A credence of 1 in a false
proposition will get a Brier score of 1—the worst score
possible. An intermediate credence of .6 will get a Brier score of
.16 if the proposition is true, and .36 if it is false.

Given a particular scoring rule R, we can develop a measure
of process reliability (Dunn 2015; Tang forthcoming). Let X be
some credence-forming process: that is, a process that outputs
credences in a range of propositions. We can use R to score all
of the credences that X produces. Average all of these scores,
and we have a measure of X’s degree of reliability.
Process reliabilists can then use this measure of reliability to give
an account of justification for credences: a credence is (prima
facie) justified iff it is produced by a reliable
credence-forming process. What’s the most suitable scoring rule
for process reliabilism to use? Recent work has begun to tackle this
question. In what follows, we confine ourselves to discussing two
particularly prominent scoring rules—the Brier score and a
calibration score.

Given its prominence in the literature, the Brier score is a
natural option. But using the Brier score to measure the reliability
of credence-forming processes faces challenges. For example, Dunn
(2015) and Tang (forthcoming) object that if the Brier score is used,
a credence-forming process that only outputs mid-level credences (say,
a credence of .6) will never qualify as highly reliable; hence the
credences it produces will never count as highly justified. Both Dunn
and Tang object to this consequence. For instance, Tang argues that
sometimes a particular input requires having a mid-level credence. If
I have a vague visual experience of the silhouette of a horse, then it
seems I should only have a mid-level credence that there is a horse in
front of me: a credence of .6 in this proposition might well be
justified, whereas a credence of 1 or 0 would not.

Another option is to measure the reliability of credence-forming
processes using a calibration score. To see what it means for
a credal state to be well-calibrated, consider the following example
from van Fraassen:

Consider a weather forecaster who says in the morning
that the probability of rain equals .8. That day it either rains or
does not. How good a forecaster is he? Clearly to evaluate him we must
look at his performance over a longer period of time. Calibration is
a measure of agreement between judgments and actual
frequencies… This forecaster was perfectly calibrated over the
past year, for example, if, for every number r, the proportion
of rainy days among those days on which he announced
probability r for rain, equaled r. (van Fraassen 1984:
245)

According to the calibration approach, a credence is justified iff
it’s produced by a well-calibrated process. This avoids the
objection to using the Brier score: after all, a credence-forming
process that produces mid-level credences can still be
well-calibrated.

However, the calibration approach has also elicited criticism.
Goldman (1986) asks us to imagine an agent A, 70% of whose
opinions turn out to be true. A can achieve a perfectly
calibrated credence function by adopting a .7 credence in every
proposition about which she has an opinion. However, Goldman argues
that it’s wrong to automatically conclude that A’s
credal state is perfectly reliable: if A has no good reason for
adopting a .7 credence in many of the propositions in question, then
her credal state shouldn’t count as justified. Dunn (2015)
defends the calibration approach, arguing that the relevant question
is whether the process that produced A’s credal
state is reliable. In order to answer this question, it’s not
enough to look at the truth-ratio of A’s opinions at the
actual world; rather, we should look across a range of nearby
worlds. If it’s just a matter of chance that 70% of the
propositions A has an opinion about are true, then by looking
at the truth-values of A’s opinions at nearby worlds the
calibration approach will be able to avoid the counterintuitive
consequence that A’s credal state is perfectly
reliable.

Weng Hong Tang (forthcoming) objects to the calibration approach on
the grounds that a credence-forming process can be well-calibrated
even though that process is insensitive to relevant evidence. In light
of the perceived shortcomings of the calibration approach (and those
of alternative scoring rules), Tang proposes a synthesis of
reliabilism and evidentialism, where evidentialism can roughly be
understood as the view that a belief’s justification is
determined by how well it is supported by the evidence that the
believer has. According to Tang’s proposal, a credence of
\(C(p)\) is only justified if it is based on some ground g, such that
the objective probability of the credence having a true content
given g approximates \(C(p)\). (Other syntheses of reliabilism
and evidentialism are discussed in section 6.2.)

Only recently have philosophers started to systematically explore
the possibility of using scoring rules to provide a reliabilist theory
of credal justification. However, given its position at the
intersection of traditional and formal epistemology, this will likely
prove to be a rich and important area of ongoing research.

A number of theories have “branched off” from process
reliabilism, borrowing some key ideas but parting company with respect
to others. This section discusses two such cousins of process
reliabilism: virtue reliabilism and syntheses of reliabilism and
evidentialism.

As its label suggests, virtue reliabilism is a branch of virtue
epistemology that emerged in the mid-1980s in the wake of process
reliabilism and shares some significant features with it. In
particular, one of its central theoretical notions, that of an
epistemic competence, resembles that of a reliable belief-forming
process type. And its notion of the exercise of an epistemic
competence resembles that of a token of a reliable process. Leading
proponents of virtue reliabilism include Ernest Sosa (1991, 2007,
2010, 2015), John Greco (1999, 2009,
2010) and Duncan
Pritchard (2012). Here we will focus primarily on Sosa’s
version.

Most virtue reliabilists do not explicitly use the notion of a
“reliable process”, preferring instead the notions of
“competence”, “virtue”, “skill”
(Sosa) or “ability” (Greco, Pritchard). How should we
understand these notions? Sosa often characterizes competences in
terms of dispositions, for instance:

A competence is a certain sort of disposition to
succeed when you try. So, exercise of a competence involves aiming at
a certain outcome. It is a competence in part because it is a
disposition to succeed reliably enough when one makes such
attempts… It is thus tied to a conditional of the form: if one
tried to \(\phi\), one would (likely enough) succeed. (2015:
96)

Epistemic competences—the sort of competence that is
relevant to epistemology—are dispositions of a specific variety:
dispositions to arrive at the truth.

One question that arises for such accounts of competence is how we
are to understand the dispositions in question. Are they general
dispositions of an agent to arrive at the truth about some matter? Or
are they to be understood as implicitly relativized to belief-forming
processes or methods, in which case an epistemic competence is really
of the form: a disposition to arrive at the truth when employing
process P?

From a process reliabilist perspective, it’s necessary to
relativize the dispositions to belief-forming processes or
methods. After all, process reliabilists will insist that in order to
know whether an agent’s belief that p is justified or
counts as knowledge, it’s not enough to know whether the agent
is generally disposed to arrive at truths about p-related
matters. Instead, we’ll need to know whether the agent’s
particular belief that p was the result of a reliable
process. (After all, an agent could form the belief that p via
an ultra-reliable process, even if she’s generally disposed to
form beliefs about p-related matters in highly unreliable
ways.) In effect, committed process reliabilists will suggest that
virtue reliabilists face a dilemma: either epistemic competences are
general dispositions of the agent, in which case they won’t be
able to perform the various jobs required of them (specifically,
explaining whether a belief is justified, or amounts to knowledge), or
they are implicitly relativized to processes, in which case epistemic
competences are not significantly different from reliable
belief-forming processes. In the latter case, epistemic competences
“collapse” into reliable processes.

In at least some discussions of epistemic competences, virtue
reliabilists indicate a willingness to relativize epistemic
competences to processes. For example, Sosa describes good eyesight
and color vision as paradigmatic epistemic competences (Sosa 1991:
271, 2010: 467)—both of which are also standard examples of
reliable processes. Similarly, Greco (1999) suggests that the
intellectual virtues are processes that form stable components of an
individual’s cognitive character—suggesting that they are
a type of reliable process.

If epistemic competences are understood as involving reliable
processes, then virtue reliabilism inherits many of the challenges
facing process reliabilism—in particular, the generality
problem. (In virtue reliabilist terms, this will amount to the
question: “How exactly should we type epistemic
competences?”) Of course, this result is unsurprising if
Comesaña is right that the generality problem is a problem for
everyone who tries to give an adequate theory of justified belief.

Virtue reliabilism differs from traditional process reliabilism in
its choice of analysandum. Historically process reliabilists have
focused on giving an account of justification; by contrast,
virtue reliabilists have focused on giving an account
of knowledge. However, one certainly could try to extend
one’s virtue reliabilism to justification. Indeed, if one
assumes that knowledge entails justification, being a virtue
reliabilist about the former seems to lead naturally to virtue
reliabilism about the latter. And if epistemic competences are
understood as reliable processes, the resulting virtue reliabilist
account of justification would presumably amount to a version of
process reliabilism.

Let us turn now to virtue reliabilist accounts of knowledge. How
do virtue reliabilists propose to understand knowledge in terms of
epistemic competences? There are a variety of slightly different
proposals in the literature (Greco 2009, 2010; Sosa 2007, 2015; Turri 2011). However, virtue
reliabilists typically understand knowledge as involving some sort of
explanatory relation between having a true belief and the exercise of
an epistemic competence. For instance, Sosa (2007) holds that S
knows p iff S aptly believes p,
where S’s belief is apt iff it is
correct because of the exercise of an epistemic competence (see
also Greco 2009, 2010 for
a closely related account). More recently, Sosa (2010, 2015) defends a
similar account couched in terms of “manifestation”:
knowledge is belief whose correctness manifests the agent’s
epistemic competence (see Turri 2011 for a similar account).

How do such accounts handle Gettier cases? Sosa 2007: 94–97
discusses Lehrer’s (1965) Nogot/Havit case, in which a subject S truly
believes that someone here owns a Ford, but he only does so on the
basis of Nogot’s misleading testimony. Sosa claims that
while S holds this belief because of the exercise of an
epistemic competence, S’s belief isn’t
correct because of the exercise of an epistemic
competence. This explanation raises important questions about how to
understand the relevant “because of” relation here: what
exactly is the difference between a true belief being held because of
an epistemic competence, and a belief being correct because of an
epistemic competence? (After all, the exercise of the competence
virtually never plays any role in making true the proposition
believed. This proposition is true because of what happens in the
world.) Other ways of fleshing out the details of a virtue reliabilist
analysis raise similar questions. (See Lackey 2007 for critical
discussion of virtue reliabilist theories that appeal to a notion of
“epistemic credit”.)

Even if a virtue reliabilist account of knowledge can handle some
Gettier cases, there remains a question of whether it will be able to
handle the full spectrum of Gettier cases. One case that has been
thought to cause particular trouble for virtue reliabilists is the
fake barn scenario (discussed by Goldman 1976, credited to Carl
Ginet). In the fake barn scenario, Henry sees from the road the one
genuine barn in an area filled with many convincing barn
façades. Henry forms a true belief that there’s a barn in
front of him; what’s more, the fact that he correctly believes
there’s a barn in front of him seems to be causally explained by
an exercise of his visual competence.

In response, one option is simply to embrace the conclusion that
Henry’s belief amounts to knowledge (Sosa 2010). This strikes
many to be counterintuitive: the “received” view on fake
barn cases is that they are cases of non-knowledge. It is true that a
recent experimental philosophy study found that lay people do
attribute knowledge to protagonists in fake-barn cases, although they
are less inclined to do so than in unproblematic cases of knowledge
(Colaco et al. 2014). This result may lend support to Henry’s
knowing. However, if, as many philosophers claim, philosophers
themselves have more expertise than laypersons do in judging such
cases, the power of the indicated result is debatable. It is
questionable how much this finding rescues virtue reliabilists from a
potentially severe counterexample.

Another response is to abandon the hope that virtue reliabilism on
its own will solve every Gettier case. Pritchard (2012) takes this
line, opting for a view that combines elements of virtue epistemology
with a safety requirement on knowledge (where, again, safety is
roughly the requirement that the belief in question couldn’t
easily have been held falsely). On Pritchard’s view,
Henry’s belief that he sees a barn is unsafe, hence fails to
count as knowledge.

A full assessment of these issues is beyond the scope of the
current article. (For further discussion of whether virtue reliabilism
can handle Gettier cases, see Miracchi
2015.[2]) This
much is clear: one feature that distinguishes virtue reliabilism from
classical process reliabilism is its distinctive treatment of
knowledge. However, this treatment gives rise to serious questions and
challenges which have not yet been fully resolved.

Process reliabilism and evidentialism have long been viewed as
competitors, even antitheses of one another, with one of them
(reliabilism) being a paradigm of externalism and the other
(evidentialism) a paradigm of internalism. However, Juan
Comesaña (2010) and Alvin Goldman (2011), both reliabilists,
have toyed with the prospect of combining the best features of each
theory to form a new theory that evades earlier problems. From the
perspective of this entry, the chief question is whether such an
accommodation helps reliabilism with some of its problems while not
abandoning its essential features.

Juan Comesaña (2010) suggests that a hybrid of reliabilism
and evidentialism along the following lines can help evade some of the
problems facing traditional reliabilism:

Proto-evidentialist Reliabilism:S’s
belief that P is justified if and only if that belief was
produced by a process X which includes some evidence e
and:

e doesn’t include any beliefs of S
and X is actually reliable; or

e includes beliefs of S, all of these beliefs are
justified, and X is conditionally actually reliable.

(Note that this is not Comesaña’s final theory. His
final proposal—“Evidentialist
Reliabilism”—involves certain further features designed to
help solve the generality problem. For simplicity, we focus on his
more basic proposal for integrating evidentialism with
reliabilism.)

There are two main respects in which this departs from more
traditional versions of reliabilism. The most obvious is that it
involves an evidential requirement. This is intended to help
with the case of Norman the clairvoyant. One crucial feature of
Norman’s situation is that he has no evidence for or against his
clairvoyance powers, or regarding the whereabouts of the President.
This is at least one of the reasons (says Comesaña) why we have
the intuition that Norman is not justified. By imposing an evidential
requirement on justification, we seem to solve the Norman
problem.

However, there remains the question of how to understand the
relevant notion of “evidence”. As we’ve seen
(§2), traditional process reliabilists resisted defining
“justification” in terms of evidence because they
didn’t want an analysis that relied on any unreduced epistemic
notions (Goldman 1979). But even for those who do not share these
reductive ambitions, it’s natural to want at least some account
of the sort of evidence that Proto-Evidentialist Reliabilism
invokes.

Comesaña suggests following Conee and Feldman
(2004) in opting for a
“mentalist” construal of our evidence, according to which
our evidence ultimately consists in various mental states. For those
who find this approach promising, there remains the difficult question
of which mental states constitute a subject’s
evidence. (Are they conscious experiences? States that are accessible
to consciousness? Beliefs?) A fully worked out hybrid of reliabilism
and evidentialism would hopefully include answers to these
questions.

A less obvious departure from traditional forms of reliabilism is
the lack of any overtly historical condition on
justifiedness. Traditional forms of reliabilism make epistemic status
of a belief at a time t depend not only on features of the
agent at t, but also on facts about how the believer acquired
the belief in question. Here’s an example that motivates this
“historicist” dimension to traditional reliabilism
(Goldman 1999). Last year Sally read about the health benefits of
broccoli in a New York Times science section story. She then forms a
justified belief in broccoli’s beneficial effects. She still
retains that belief today but no longer recalls the evidence she had
upon first reading the story. And she hasn’t encountered any
further evidence in the interim, from any kind of source. Isn’t
her belief in broccoli’s beneficial effects still justified?
Presumably this is because of her past acquisition. True, she also has
a different kind of evidence, namely, her (justified) belief that
whenever she seems to remember a (putative) fact it is usually
true. But this is not her entire evidence. It is an important
determinant of her belief’s J-status at t that she was
justified in forming it originally on the basis of good evidence (of
another kind). Had her original belief been based on very poor
evidence, e.g., reading a similar story in an untrustworthy news
source, so that the belief wasn’t justified from the start, her
belief at time t would be unjustified—or at least
much less justified. This indicates that the evidence she
acquired originally still has some impact on the J-status of
her belief at t. It is also important, of course, that the
central process she uses to retain her broccoli belief, namely,
preservative memory, is (conditionally) reliable. Its output beliefs
tend to be true if its input beliefs are true. In light of such
considerations, some process reliabilists will be reluctant to abandon
a “historicist” component.

Thus far we have discussed Comesaña’s rationale for a
synthesis between reliabilism and evidentialism. What about
Goldman’s rationale? One rationale, presented
“up-front” in his article (Goldman 2011), is to advance a
“two-dimensional” approach to justification, an approach
that makes room for a “degree of support” dimension of
justification as well as a “proper causal generation”
dimension. Evidentialism is centered on the “degree of
support” dimension (sometimes phrased in terms of the
“fittingness” of someone’s taking some doxastic
attitude toward a proposition to the evidence that the person has) and
offers little with respect to the second dimension. Reliabilism does
the reverse: it does well on the causal generation dimension but
poorly on the degree of support dimension. Why not add something to
reliabilism to repair this possible lacuna? One might respond that
this maneuver would be radically out of keeping with
reliabilism. Doesn’t reliabilism utterly reject the relevance of
evidence and strength of evidence in its whole approach?

It is true that process reliabilism has traditionally made no
explicit reference to evidence—it never uses this term in its
central theoretical principles. Nonetheless, it is well-positioned to
make up for this deficit without much awkwardness. Consider all of the
mental or psychological states that reliabilism traditionally
appeals to. In addition to the processes it discusses, there
are also states that serve as inputs to those
processes. This includes both doxastic states (beliefs, primarily)
and various experiences (perceptual, memorial, etc.). Although
reliabilists never call these states “evidence”
(nor refer to their contents as “evidence”), there is no
reason why this couldn’t be
done.[3] This
remains an open question. The same points may be made in the language
of “reasons” rather than “evidence”. Although
traditional process reliabilists don’t find a place for reasons
in their story, it is easy for them to say that justified belief
states that are inputs to their beloved processes constitute reasons
for their holding the output beliefs. Their quality as reasons may
depend on their relations of support vis-à-vis the propositions
inferred (and believed). Here again the upshot would be a
two-dimensional theory of justification, according to which the
J-status of a belief is determined by both (i) the reliability of the
belief-forming process, and (ii) the support provided by the
evidence/reasons that serve as inputs to this process. Goldman makes
some suggestions about how this would go, but such a task remains to
be done more thoroughly. And if one hopes to fuse the two dimensions
into a single measure of justifiedness, this seems conceivable but far
from straightforward.